The 6-car trains were built in Japan by Hitachi and operate at a maximum speed of 140 mph (225 km/h) under 25kV AC overhead electrification on High Speed 1, and 100 mph (161 km/h) on 750 V DC third rail supply on conventional lines.

The use of the high-speed trains as part of the transport infrastructure for the Olympic park formed part of the original bid for the 2012 Summer Olympics.[9][10] The service was named the Olympic Javelin Shuttle, and the name Javelin has become a common name for the trains.[11] The Olympic services began 28 July 2012.[12]

In December 2003 formal approval was given to run domestic services on the planned Channel Tunnel Rail Link (CTRL, now known as High Speed 1, or HS1) in Kent, England,[13] Preliminary consultations for a new franchise including then CTRL, and for rolling stock to operate the 'CTRL Domestic' services were to begin in 2004.[14] In 2005 the proposed high-speed services were combined with those from the former South Eastern rail franchise to form the Integrated Kent franchise (IKF).[15]

In October 2004 Hitachi was announced as the preferred bidder to supply high-speed trains for the CTRL services,[8][16][17] and in June 2005 the £250 million contract was signed with Hitachi Europe Ltd as supplier of 28 trainsets, with HSBC Rail acting as the financier (ROSCO), and with an expected service date of 2009.[18] In November 2005 the Department for Transport announced Govia as the new operator of the IKF.[19]

The contract was Hitachi's first rail vehicle sold to a UK or European customer.[20][21] It had previously worked with HSBC Rail and UK rail authorities between 2002 and 2003 to demonstrate the suitability and conformance of Hitachi's traction system with the UK rail network, including test of the use of AC induction motors, and Electromagnetic compatibility tests.[22][note 2]

Construction of the CTRL (High Speed 1) was complete in November 2007. By 2008 the initially planned 'CTRL Domestic' services (2003) from London St Pancras to Gravesend, and Canterbury West and Folkestone Central via Ashford had been expanded in scope to include services to Medway Towns, East Kent and Dover.[23]

A twenty-ninth train was added to the order agreement by franchise holder Southeastern to provide additional capacity.[3]

The contract for the trains included maintenance of the trains;[24] a consortium ('DEPCO') including HSBC Rail (finance), Fitzpatrick Contractors Ltd (construction), RPS Burks Green (architects/civil engineers), EMCOR UK (mechanical and electrical plant) and GrantRail (trackwork) constructed a new maintenance depot building at Ashford and the updating of the existing depot site.[5][25] The Ashford train depot was formally opened on 2 October 2007,[26] constructed on the site of the Ashford Down Yard Carriage Sidings;[27][note 3] the facility included a five-track trainshed with bogie drop made by BBM and train lifting equipment from Mechan. A second building housed a wheel lathe from Sculfort. Other facilities included carriage washing plant, a 25kV OHL test track, and sidings for rolling stock.[25]

A Class 395 train simulator supplied by Corys TESS was acquired for use at the Southeastern's training centre in Ashford for driver training,[28] Southeastern's co-parent company SNCF also assisted with high-speed driver training.[29]

The DEPCO consortium also updated another existing depot at Ramsgate (see Ramsgate train depot) for the IKF with facilities including storage sidings for the Class 395 trains and light maintenance facilities.[25]

The first train was delivered from Japan to Southampton Docks on 23 August 2007.[31]Homologation testing was undertaken by Serco,[32] SNCF International assisted with testing of KVB and TVM 430 signalling systems, with speeds of 240 km/h (150 mph) attained in January 2008.[30][33][34][35] After successful testing of four units (delivered by March 2008) shipping of the main production tranche began in December 2008.[36][37] The final three trains arrived in the UK in August 2009,[1][3][38] with the final train delivered to Southeastern on 11 December 2009.[39]

The performance metric of 4,000 miles fault free running was achieved six months ahead of schedule, allowing a 'preview' service to be offered by June 2009 between London St Pancras and Ashford via Ebbsfleet, allowing further train testing,[40] which achieved a 99% punctuality rate in the first month of operations.[1][3][41] In September 2009 preliminary services to the Kent coast (Dover via Folkestone, and Ramsgate via Canterbury) also began.[42][43] Preview services on the North Kent line began in November 2009.[44]

In September 2010 it was reported that passengers were experiencing alarming 'wobbles' on tunnel sections. The problem was described by Southeastern as non-dangerous, and trains were fitted with dampers to prevent the problem from recurring.[45]

A full regular service commenced on 13 December 2009.[2] Initial services included a half-hourly north Kent service via Stratford, Ebbsfleet, Gravesend, Strood, Rochester, Chatham, Gillingham, Rainham, and Sittingbourne to Faversham, a half-hourly service to east Kent via Stratford, Ebbsfleet, Ashford with one train continuing to Margate via Canterbury West, Ramsgate and Broadstairs, and the other to Dover via Folkestone West and Folkestone Central.[46] Seven million journeys were made in the first year of operation,[47]

The introduction of the trains was generally successful, with good reliability and passenger satisfaction figures; the new high-speed services also caused an increase in passenger numbers above that already being experienced on the Kent network.[48] On introduction timetabled journeys to London from Ebbsfleet were reduced from 51 to 18 minutes, whilst trains using the entire length of High Speed 1 (starting in Ashford) had timetabled journeys reduced by around 45 minutes.[49] However, the service has been criticised as being of limited use to many London commuters because trains terminate at St Pancras. Additionally, the change in service patterns to accommodate high-speed trains resulted in some non-high-speed services in Kent becoming slower.[50]

In May 2011 a limited service from Maidstone West via Strood and Gravesend started.[51] followed in September 2011 by a limited service from Sandwich via Deal to London St Pancras, partially subsidised by Kent County Council.[52] In the second year of operation total passenger numbers were over eight million.[53]

The 400 Series mini-shinkansen and Hitachi's A Train design form the basis of the Class 395 design.[8] From the 400 series the class inherits the same 6-car 20 m carriage with doors at one-third and two-thirds along the carriage.[note 4] Both are designed for operations at high speed on newly built lines as well as at lower speed on conventional legacy lines.[54] Unlike the steel-bodied Series 400, the Class 395 has its carbody (walls, roof, floor) formed from friction stir welded double-walled hollow extruded aluminium body panels, a technology Hitachi considers part of its A-Train train family specification.[8][55]

The train consists of six-car units, with all axles on the middle four cars powered. The outer cars are unpowered, but mount the pantographs (giving a formation DPT1+MS1+MS2+MS3+MS4+DPT2.[note 1]). The bogies are bolsterless, with both powered and unpowered bogies sharing a common design to simplify maintenance.[55] Each 6-car unit can work in multiple with another, creating 12-car trains. Coupling is automated and is designed to take less than 60 seconds.[55][56]

For reliability, passenger doors use a relatively simple sliding pneumatic system already in use and development for several decades on Shinkansen trains.[5][57] The brake system was supplied by Faiveley.[58] Approximately 40% of the train equipment by value was provided by European suppliers.

There are 340 seats per 6-car train, in standard class [2+2] formation with 12 additional tip up seats in a wheelchair area. There are two toilets per unit, one of which is equipped for disabled access.[6]

Each train has a Train Management System (TMS) including equipment monitoring systems, communications, air-conditioning, etc., and equipment control including Selective Door Operation (SDO). The SDO system uses GPS and train speed integration to estimate position.[60]

^"London 2012 venue: Olympic zone". BBC News. 16 January 2004. London's bid team say the Olympic Park will be served by 10 train lines, including 'Olympic Javelin' bullet trains providing a link to the city centre in seven minutes.